refactor: replace json.Marshal and json.Unmarshal with sjson and gjson

Optimized the handling of JSON serialization and deserialization by replacing redundant `json.Marshal` and `json.Unmarshal` calls with `sjson` and `gjson`. Introduced a `marshalJSONValue` utility for compact JSON encoding, improving performance and code simplicity. Removed unused `encoding/json` imports.

internal/translator/gemini/claude/gemini_claude_request.go

@@ -7,10 +7,8 @@ package claude
 
 import (
 	"bytes"
-	"encoding/json"
 	"strings"
 
-	client "github.com/router-for-me/CLIProxyAPI/v6/internal/interfaces"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/translator/gemini/common"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	"github.com/tidwall/gjson"
@@ -34,92 +32,100 @@ func ConvertClaudeRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 	rawJSON := bytes.Clone(inputRawJSON)
 	rawJSON = bytes.Replace(rawJSON, []byte(`"url":{"type":"string","format":"uri",`), []byte(`"url":{"type":"string",`), -1)
 
+	// Build output Gemini CLI request JSON
+	out := `{"contents":[]}`
+	out, _ = sjson.Set(out, "model", modelName)
+
 	// system instruction
-	var systemInstruction *client.Content
-	systemResult := gjson.GetBytes(rawJSON, "system")
-	if systemResult.IsArray() {
-		systemResults := systemResult.Array()
-		systemInstruction = &client.Content{Role: "user", Parts: []client.Part{}}
-		for i := 0; i < len(systemResults); i++ {
-			systemPromptResult := systemResults[i]
-			systemTypePromptResult := systemPromptResult.Get("type")
-			if systemTypePromptResult.Type == gjson.String && systemTypePromptResult.String() == "text" {
-				systemPrompt := systemPromptResult.Get("text").String()
-				systemPart := client.Part{Text: systemPrompt}
-				systemInstruction.Parts = append(systemInstruction.Parts, systemPart)
+	if systemResult := gjson.GetBytes(rawJSON, "system"); systemResult.IsArray() {
+		systemInstruction := `{"role":"user","parts":[]}`
+		hasSystemParts := false
+		systemResult.ForEach(func(_, systemPromptResult gjson.Result) bool {
+			if systemPromptResult.Get("type").String() == "text" {
+				textResult := systemPromptResult.Get("text")
+				if textResult.Type == gjson.String {
+					part := `{"text":""}`
+					part, _ = sjson.Set(part, "text", textResult.String())
+					systemInstruction, _ = sjson.SetRaw(systemInstruction, "parts.-1", part)
+					hasSystemParts = true
+				}
 			}
-		}
-		if len(systemInstruction.Parts) == 0 {
-			systemInstruction = nil
+			return true
+		})
+		if hasSystemParts {
+			out, _ = sjson.SetRaw(out, "system_instruction", systemInstruction)
 		}
 	}
 
 	// contents
-	contents := make([]client.Content, 0)
-	messagesResult := gjson.GetBytes(rawJSON, "messages")
-	if messagesResult.IsArray() {
-		messageResults := messagesResult.Array()
-		for i := 0; i < len(messageResults); i++ {
-			messageResult := messageResults[i]
+	if messagesResult := gjson.GetBytes(rawJSON, "messages"); messagesResult.IsArray() {
+		messagesResult.ForEach(func(_, messageResult gjson.Result) bool {
 			roleResult := messageResult.Get("role")
 			if roleResult.Type != gjson.String {
-				continue
+				return true
 			}
 			role := roleResult.String()
 			if role == "assistant" {
 				role = "model"
 			}
-			clientContent := client.Content{Role: role, Parts: []client.Part{}}
+
+			contentJSON := `{"role":"","parts":[]}`
+			contentJSON, _ = sjson.Set(contentJSON, "role", role)
+
 			contentsResult := messageResult.Get("content")
 			if contentsResult.IsArray() {
-				contentResults := contentsResult.Array()
-				for j := 0; j < len(contentResults); j++ {
-					contentResult := contentResults[j]
-					contentTypeResult := contentResult.Get("type")
-					if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
-						prompt := contentResult.Get("text").String()
-						clientContent.Parts = append(clientContent.Parts, client.Part{Text: prompt})
-					} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "tool_use" {
+				contentsResult.ForEach(func(_, contentResult gjson.Result) bool {
+					switch contentResult.Get("type").String() {
+					case "text":
+						part := `{"text":""}`
+						part, _ = sjson.Set(part, "text", contentResult.Get("text").String())
+						contentJSON, _ = sjson.SetRaw(contentJSON, "parts.-1", part)
+
+					case "tool_use":
 						functionName := contentResult.Get("name").String()
 						functionArgs := contentResult.Get("input").String()
-						var args map[string]any
-						if err := json.Unmarshal([]byte(functionArgs), &args); err == nil {
-							clientContent.Parts = append(clientContent.Parts, client.Part{
-								FunctionCall:     &client.FunctionCall{Name: functionName, Args: args},
-								ThoughtSignature: geminiClaudeThoughtSignature,
-							})
+						argsResult := gjson.Parse(functionArgs)
+						if argsResult.IsObject() && gjson.Valid(functionArgs) {
+							part := `{"thoughtSignature":"","functionCall":{"name":"","args":{}}}`
+							part, _ = sjson.Set(part, "thoughtSignature", geminiClaudeThoughtSignature)
+							part, _ = sjson.Set(part, "functionCall.name", functionName)
+							part, _ = sjson.SetRaw(part, "functionCall.args", functionArgs)
+							contentJSON, _ = sjson.SetRaw(contentJSON, "parts.-1", part)
 						}
-					} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "tool_result" {
+
+					case "tool_result":
 						toolCallID := contentResult.Get("tool_use_id").String()
-						if toolCallID != "" {
-							funcName := toolCallID
-							toolCallIDs := strings.Split(toolCallID, "-")
-							if len(toolCallIDs) > 1 {
-								funcName = strings.Join(toolCallIDs[0:len(toolCallIDs)-1], "-")
-							}
-							responseData := contentResult.Get("content").Raw
-							functionResponse := client.FunctionResponse{Name: funcName, Response: map[string]interface{}{"result": responseData}}
-							clientContent.Parts = append(clientContent.Parts, client.Part{FunctionResponse: &functionResponse})
+						if toolCallID == "" {
+							return true
 						}
+						funcName := toolCallID
+						toolCallIDs := strings.Split(toolCallID, "-")
+						if len(toolCallIDs) > 1 {
+							funcName = strings.Join(toolCallIDs[0:len(toolCallIDs)-1], "-")
+						}
+						responseData := contentResult.Get("content").Raw
+						part := `{"functionResponse":{"name":"","response":{"result":""}}}`
+						part, _ = sjson.Set(part, "functionResponse.name", funcName)
+						part, _ = sjson.Set(part, "functionResponse.response.result", responseData)
+						contentJSON, _ = sjson.SetRaw(contentJSON, "parts.-1", part)
 					}
-				}
-				contents = append(contents, clientContent)
+					return true
+				})
+				out, _ = sjson.SetRaw(out, "contents.-1", contentJSON)
 			} else if contentsResult.Type == gjson.String {
-				prompt := contentsResult.String()
-				contents = append(contents, client.Content{Role: role, Parts: []client.Part{{Text: prompt}}})
+				part := `{"text":""}`
+				part, _ = sjson.Set(part, "text", contentsResult.String())
+				contentJSON, _ = sjson.SetRaw(contentJSON, "parts.-1", part)
+				out, _ = sjson.SetRaw(out, "contents.-1", contentJSON)
 			}
-		}
+			return true
+		})
 	}
 
 	// tools
-	var tools []client.ToolDeclaration
-	toolsResult := gjson.GetBytes(rawJSON, "tools")
-	if toolsResult.IsArray() {
-		tools = make([]client.ToolDeclaration, 1)
-		tools[0].FunctionDeclarations = make([]any, 0)
-		toolsResults := toolsResult.Array()
-		for i := 0; i < len(toolsResults); i++ {
-			toolResult := toolsResults[i]
+	if toolsResult := gjson.GetBytes(rawJSON, "tools"); toolsResult.IsArray() {
+		hasTools := false
+		toolsResult.ForEach(func(_, toolResult gjson.Result) bool {
 			inputSchemaResult := toolResult.Get("input_schema")
 			if inputSchemaResult.Exists() && inputSchemaResult.IsObject() {
 				inputSchema := inputSchemaResult.Raw
@@ -129,30 +135,19 @@ func ConvertClaudeRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 				tool, _ = sjson.Delete(tool, "input_examples")
 				tool, _ = sjson.Delete(tool, "type")
 				tool, _ = sjson.Delete(tool, "cache_control")
-				var toolDeclaration any
-				if err := json.Unmarshal([]byte(tool), &toolDeclaration); err == nil {
-					tools[0].FunctionDeclarations = append(tools[0].FunctionDeclarations, toolDeclaration)
+				if gjson.Valid(tool) && gjson.Parse(tool).IsObject() {
+					if !hasTools {
+						out, _ = sjson.SetRaw(out, "tools", `[{"functionDeclarations":[]}]`)
+						hasTools = true
+					}
+					out, _ = sjson.SetRaw(out, "tools.0.functionDeclarations.-1", tool)
 				}
 			}
+			return true
+		})
+		if !hasTools {
+			out, _ = sjson.Delete(out, "tools")
 		}
-	} else {
-		tools = make([]client.ToolDeclaration, 0)
-	}
-
-	// Build output Gemini CLI request JSON
-	out := `{"contents":[]}`
-	out, _ = sjson.Set(out, "model", modelName)
-	if systemInstruction != nil {
-		b, _ := json.Marshal(systemInstruction)
-		out, _ = sjson.SetRaw(out, "system_instruction", string(b))
-	}
-	if len(contents) > 0 {
-		b, _ := json.Marshal(contents)
-		out, _ = sjson.SetRaw(out, "contents", string(b))
-	}
-	if len(tools) > 0 && len(tools[0].FunctionDeclarations) > 0 {
-		b, _ := json.Marshal(tools)
-		out, _ = sjson.SetRaw(out, "tools", string(b))
 	}
 
 	// Map Anthropic thinking -> Gemini thinkingBudget/include_thoughts when enabled

internal/translator/gemini/claude/gemini_claude_response.go

@@ -9,7 +9,6 @@ package claude
 import (
 	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
 	"strings"
 	"sync/atomic"
@@ -282,22 +281,16 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 
 	root := gjson.ParseBytes(rawJSON)
 
-	response := map[string]interface{}{
-		"id":            root.Get("responseId").String(),
-		"type":          "message",
-		"role":          "assistant",
-		"model":         root.Get("modelVersion").String(),
-		"content":       []interface{}{},
-		"stop_reason":   nil,
-		"stop_sequence": nil,
-		"usage": map[string]interface{}{
-			"input_tokens":  root.Get("usageMetadata.promptTokenCount").Int(),
-			"output_tokens": root.Get("usageMetadata.candidatesTokenCount").Int() + root.Get("usageMetadata.thoughtsTokenCount").Int(),
-		},
-	}
+	out := `{"id":"","type":"message","role":"assistant","model":"","content":[],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":0,"output_tokens":0}}`
+	out, _ = sjson.Set(out, "id", root.Get("responseId").String())
+	out, _ = sjson.Set(out, "model", root.Get("modelVersion").String())
+
+	inputTokens := root.Get("usageMetadata.promptTokenCount").Int()
+	outputTokens := root.Get("usageMetadata.candidatesTokenCount").Int() + root.Get("usageMetadata.thoughtsTokenCount").Int()
+	out, _ = sjson.Set(out, "usage.input_tokens", inputTokens)
+	out, _ = sjson.Set(out, "usage.output_tokens", outputTokens)
 
 	parts := root.Get("candidates.0.content.parts")
-	var contentBlocks []interface{}
 	textBuilder := strings.Builder{}
 	thinkingBuilder := strings.Builder{}
 	toolIDCounter := 0
@@ -307,10 +300,9 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 		if textBuilder.Len() == 0 {
 			return
 		}
-		contentBlocks = append(contentBlocks, map[string]interface{}{
-			"type": "text",
-			"text": textBuilder.String(),
-		})
+		block := `{"type":"text","text":""}`
+		block, _ = sjson.Set(block, "text", textBuilder.String())
+		out, _ = sjson.SetRaw(out, "content.-1", block)
 		textBuilder.Reset()
 	}
 
@@ -318,10 +310,9 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 		if thinkingBuilder.Len() == 0 {
 			return
 		}
-		contentBlocks = append(contentBlocks, map[string]interface{}{
-			"type":     "thinking",
-			"thinking": thinkingBuilder.String(),
-		})
+		block := `{"type":"thinking","thinking":""}`
+		block, _ = sjson.Set(block, "thinking", thinkingBuilder.String())
+		out, _ = sjson.SetRaw(out, "content.-1", block)
 		thinkingBuilder.Reset()
 	}
 
@@ -345,21 +336,15 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 
 				name := functionCall.Get("name").String()
 				toolIDCounter++
-				toolBlock := map[string]interface{}{
-					"type":  "tool_use",
-					"id":    fmt.Sprintf("tool_%d", toolIDCounter),
-					"name":  name,
-					"input": map[string]interface{}{},
+				toolBlock := `{"type":"tool_use","id":"","name":"","input":{}}`
+				toolBlock, _ = sjson.Set(toolBlock, "id", fmt.Sprintf("tool_%d", toolIDCounter))
+				toolBlock, _ = sjson.Set(toolBlock, "name", name)
+				inputRaw := "{}"
+				if args := functionCall.Get("args"); args.Exists() && gjson.Valid(args.Raw) && args.IsObject() {
+					inputRaw = args.Raw
 				}
-
-				if args := functionCall.Get("args"); args.Exists() {
-					var parsed interface{}
-					if err := json.Unmarshal([]byte(args.Raw), &parsed); err == nil {
-						toolBlock["input"] = parsed
-					}
-				}
-
-				contentBlocks = append(contentBlocks, toolBlock)
+				toolBlock, _ = sjson.SetRaw(toolBlock, "input", inputRaw)
+				out, _ = sjson.SetRaw(out, "content.-1", toolBlock)
 				continue
 			}
 		}
@@ -368,8 +353,6 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 	flushThinking()
 	flushText()
 
-	response["content"] = contentBlocks
-
 	stopReason := "end_turn"
 	if hasToolCall {
 		stopReason = "tool_use"
@@ -385,19 +368,13 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 			}
 		}
 	}
-	response["stop_reason"] = stopReason
+	out, _ = sjson.Set(out, "stop_reason", stopReason)
 
-	if usage := response["usage"].(map[string]interface{}); usage["input_tokens"] == int64(0) && usage["output_tokens"] == int64(0) {
-		if usageMeta := root.Get("usageMetadata"); !usageMeta.Exists() {
-			delete(response, "usage")
-		}
+	if inputTokens == int64(0) && outputTokens == int64(0) && !root.Get("usageMetadata").Exists() {
+		out, _ = sjson.Delete(out, "usage")
 	}
 
-	encoded, err := json.Marshal(response)
-	if err != nil {
-		return ""
-	}
-	return string(encoded)
+	return out
 }
 
 func ClaudeTokenCount(ctx context.Context, count int64) string {

internal/translator/gemini/openai/chat-completions/gemini_openai_request.go

@@ -320,7 +320,7 @@ func ConvertOpenAIRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 								log.Warnf("Failed to set default schema type for tool '%s': %v", fn.Get("name").String(), errSet)
 								continue
 							}
-							fnRaw, errSet = sjson.Set(fnRaw, "parametersJsonSchema.properties", map[string]interface{}{})
+							fnRaw, errSet = sjson.SetRaw(fnRaw, "parametersJsonSchema.properties", `{}`)
 							if errSet != nil {
 								log.Warnf("Failed to set default schema properties for tool '%s': %v", fn.Get("name").String(), errSet)
 								continue
@@ -335,7 +335,7 @@ func ConvertOpenAIRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 							log.Warnf("Failed to set default schema type for tool '%s': %v", fn.Get("name").String(), errSet)
 							continue
 						}
-						fnRaw, errSet = sjson.Set(fnRaw, "parametersJsonSchema.properties", map[string]interface{}{})
+						fnRaw, errSet = sjson.SetRaw(fnRaw, "parametersJsonSchema.properties", `{}`)
 						if errSet != nil {
 							log.Warnf("Failed to set default schema properties for tool '%s': %v", fn.Get("name").String(), errSet)
 							continue

internal/translator/gemini/openai/chat-completions/gemini_openai_response.go

@@ -8,7 +8,6 @@ package chat_completions
 import (
 	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
 	"strings"
 	"sync/atomic"
@@ -173,21 +172,14 @@ func ConvertGeminiResponseToOpenAI(_ context.Context, _ string, originalRequestR
 					mimeType = "image/png"
 				}
 				imageURL := fmt.Sprintf("data:%s;base64,%s", mimeType, data)
-				imagePayload, err := json.Marshal(map[string]any{
-					"type": "image_url",
-					"image_url": map[string]string{
-						"url": imageURL,
-					},
-				})
-				if err != nil {
-					continue
-				}
+				imagePayload := `{"image_url":{"url":""},"type":"image_url"}`
+				imagePayload, _ = sjson.Set(imagePayload, "image_url.url", imageURL)
 				imagesResult := gjson.Get(template, "choices.0.delta.images")
 				if !imagesResult.Exists() || !imagesResult.IsArray() {
 					template, _ = sjson.SetRaw(template, "choices.0.delta.images", `[]`)
 				}
 				template, _ = sjson.Set(template, "choices.0.delta.role", "assistant")
-				template, _ = sjson.SetRaw(template, "choices.0.delta.images.-1", string(imagePayload))
+				template, _ = sjson.SetRaw(template, "choices.0.delta.images.-1", imagePayload)
 			}
 		}
 	}
@@ -305,21 +297,14 @@ func ConvertGeminiResponseToOpenAINonStream(_ context.Context, _ string, origina
 					mimeType = "image/png"
 				}
 				imageURL := fmt.Sprintf("data:%s;base64,%s", mimeType, data)
-				imagePayload, err := json.Marshal(map[string]any{
-					"type": "image_url",
-					"image_url": map[string]string{
-						"url": imageURL,
-					},
-				})
-				if err != nil {
-					continue
-				}
+				imagePayload := `{"image_url":{"url":""},"type":"image_url"}`
+				imagePayload, _ = sjson.Set(imagePayload, "image_url.url", imageURL)
 				imagesResult := gjson.Get(template, "choices.0.message.images")
 				if !imagesResult.Exists() || !imagesResult.IsArray() {
 					template, _ = sjson.SetRaw(template, "choices.0.message.images", `[]`)
 				}
 				template, _ = sjson.Set(template, "choices.0.message.role", "assistant")
-				template, _ = sjson.SetRaw(template, "choices.0.message.images.-1", string(imagePayload))
+				template, _ = sjson.SetRaw(template, "choices.0.message.images.-1", imagePayload)
 			}
 		}
 	}

internal/translator/gemini/openai/responses/gemini_openai-responses_response.go

@@ -377,27 +377,18 @@ func ConvertGeminiResponseToOpenAIResponses(_ context.Context, modelName string,
 		}
 
 		// Compose outputs in encountered order: reasoning, message, function_calls
-		var outputs []interface{}
+		outputsWrapper := `{"arr":[]}`
 		if st.ReasoningOpened {
-			outputs = append(outputs, map[string]interface{}{
-				"id":      st.ReasoningItemID,
-				"type":    "reasoning",
-				"summary": []interface{}{map[string]interface{}{"type": "summary_text", "text": st.ReasoningBuf.String()}},
-			})
+			item := `{"id":"","type":"reasoning","summary":[{"type":"summary_text","text":""}]}`
+			item, _ = sjson.Set(item, "id", st.ReasoningItemID)
+			item, _ = sjson.Set(item, "summary.0.text", st.ReasoningBuf.String())
+			outputsWrapper, _ = sjson.SetRaw(outputsWrapper, "arr.-1", item)
 		}
 		if st.MsgOpened {
-			outputs = append(outputs, map[string]interface{}{
-				"id":     st.CurrentMsgID,
-				"type":   "message",
-				"status": "completed",
-				"content": []interface{}{map[string]interface{}{
-					"type":        "output_text",
-					"annotations": []interface{}{},
-					"logprobs":    []interface{}{},
-					"text":        st.TextBuf.String(),
-				}},
-				"role": "assistant",
-			})
+			item := `{"id":"","type":"message","status":"completed","content":[{"type":"output_text","annotations":[],"logprobs":[],"text":""}],"role":"assistant"}`
+			item, _ = sjson.Set(item, "id", st.CurrentMsgID)
+			item, _ = sjson.Set(item, "content.0.text", st.TextBuf.String())
+			outputsWrapper, _ = sjson.SetRaw(outputsWrapper, "arr.-1", item)
 		}
 		if len(st.FuncArgsBuf) > 0 {
 			idxs := make([]int, 0, len(st.FuncArgsBuf))
@@ -416,18 +407,16 @@ func ConvertGeminiResponseToOpenAIResponses(_ context.Context, modelName string,
 				if b := st.FuncArgsBuf[idx]; b != nil {
 					args = b.String()
 				}
-				outputs = append(outputs, map[string]interface{}{
-					"id":        fmt.Sprintf("fc_%s", st.FuncCallIDs[idx]),
-					"type":      "function_call",
-					"status":    "completed",
-					"arguments": args,
-					"call_id":   st.FuncCallIDs[idx],
-					"name":      st.FuncNames[idx],
-				})
+				item := `{"id":"","type":"function_call","status":"completed","arguments":"","call_id":"","name":""}`
+				item, _ = sjson.Set(item, "id", fmt.Sprintf("fc_%s", st.FuncCallIDs[idx]))
+				item, _ = sjson.Set(item, "arguments", args)
+				item, _ = sjson.Set(item, "call_id", st.FuncCallIDs[idx])
+				item, _ = sjson.Set(item, "name", st.FuncNames[idx])
+				outputsWrapper, _ = sjson.SetRaw(outputsWrapper, "arr.-1", item)
 			}
 		}
-		if len(outputs) > 0 {
-			completed, _ = sjson.Set(completed, "response.output", outputs)
+		if gjson.Get(outputsWrapper, "arr.#").Int() > 0 {
+			completed, _ = sjson.SetRaw(completed, "response.output", gjson.Get(outputsWrapper, "arr").Raw)
 		}
 
 		// usage mapping
@@ -558,11 +547,24 @@ func ConvertGeminiResponseToOpenAIResponsesNonStream(_ context.Context, _ string
 	}
 
 	// Build outputs from candidates[0].content.parts
-	var outputs []interface{}
 	var reasoningText strings.Builder
 	var reasoningEncrypted string
 	var messageText strings.Builder
 	var haveMessage bool
+
+	haveOutput := false
+	ensureOutput := func() {
+		if haveOutput {
+			return
+		}
+		resp, _ = sjson.SetRaw(resp, "output", "[]")
+		haveOutput = true
+	}
+	appendOutput := func(itemJSON string) {
+		ensureOutput()
+		resp, _ = sjson.SetRaw(resp, "output.-1", itemJSON)
+	}
+
 	if parts := root.Get("candidates.0.content.parts"); parts.Exists() && parts.IsArray() {
 		parts.ForEach(func(_, p gjson.Result) bool {
 			if p.Get("thought").Bool() {
@@ -583,19 +585,16 @@ func ConvertGeminiResponseToOpenAIResponsesNonStream(_ context.Context, _ string
 				name := fc.Get("name").String()
 				args := fc.Get("args")
 				callID := fmt.Sprintf("call_%x_%d", time.Now().UnixNano(), atomic.AddUint64(&funcCallIDCounter, 1))
-				outputs = append(outputs, map[string]interface{}{
-					"id":     fmt.Sprintf("fc_%s", callID),
-					"type":   "function_call",
-					"status": "completed",
-					"arguments": func() string {
-						if args.Exists() {
-							return args.Raw
-						}
-						return ""
-					}(),
-					"call_id": callID,
-					"name":    name,
-				})
+				itemJSON := `{"id":"","type":"function_call","status":"completed","arguments":"","call_id":"","name":""}`
+				itemJSON, _ = sjson.Set(itemJSON, "id", fmt.Sprintf("fc_%s", callID))
+				itemJSON, _ = sjson.Set(itemJSON, "call_id", callID)
+				itemJSON, _ = sjson.Set(itemJSON, "name", name)
+				argsStr := ""
+				if args.Exists() {
+					argsStr = args.Raw
+				}
+				itemJSON, _ = sjson.Set(itemJSON, "arguments", argsStr)
+				appendOutput(itemJSON)
 				return true
 			}
 			return true
@@ -605,42 +604,24 @@ func ConvertGeminiResponseToOpenAIResponsesNonStream(_ context.Context, _ string
 	// Reasoning output item
 	if reasoningText.Len() > 0 || reasoningEncrypted != "" {
 		rid := strings.TrimPrefix(id, "resp_")
-		item := map[string]interface{}{
-			"id":                fmt.Sprintf("rs_%s", rid),
-			"type":              "reasoning",
-			"encrypted_content": reasoningEncrypted,
-		}
-		var summaries []interface{}
+		itemJSON := `{"id":"","type":"reasoning","encrypted_content":""}`
+		itemJSON, _ = sjson.Set(itemJSON, "id", fmt.Sprintf("rs_%s", rid))
+		itemJSON, _ = sjson.Set(itemJSON, "encrypted_content", reasoningEncrypted)
 		if reasoningText.Len() > 0 {
-			summaries = append(summaries, map[string]interface{}{
-				"type": "summary_text",
-				"text": reasoningText.String(),
-			})
+			summaryJSON := `{"type":"summary_text","text":""}`
+			summaryJSON, _ = sjson.Set(summaryJSON, "text", reasoningText.String())
+			itemJSON, _ = sjson.SetRaw(itemJSON, "summary", "[]")
+			itemJSON, _ = sjson.SetRaw(itemJSON, "summary.-1", summaryJSON)
 		}
-		if summaries != nil {
-			item["summary"] = summaries
-		}
-		outputs = append(outputs, item)
+		appendOutput(itemJSON)
 	}
 
 	// Assistant message output item
 	if haveMessage {
-		outputs = append(outputs, map[string]interface{}{
-			"id":     fmt.Sprintf("msg_%s_0", strings.TrimPrefix(id, "resp_")),
-			"type":   "message",
-			"status": "completed",
-			"content": []interface{}{map[string]interface{}{
-				"type":        "output_text",
-				"annotations": []interface{}{},
-				"logprobs":    []interface{}{},
-				"text":        messageText.String(),
-			}},
-			"role": "assistant",
-		})
-	}
-
-	if len(outputs) > 0 {
-		resp, _ = sjson.Set(resp, "output", outputs)
+		itemJSON := `{"id":"","type":"message","status":"completed","content":[{"type":"output_text","annotations":[],"logprobs":[],"text":""}],"role":"assistant"}`
+		itemJSON, _ = sjson.Set(itemJSON, "id", fmt.Sprintf("msg_%s_0", strings.TrimPrefix(id, "resp_")))
+		itemJSON, _ = sjson.Set(itemJSON, "content.0.text", messageText.String())
+		appendOutput(itemJSON)
 	}
 
 	// usage mapping